This invention relates to optical equipment and more particularly to a switchable optical adapter or coupler to enable the selective use of multiple cameras or photographic devices particularly during research or medical procedures.
During present day medical or surgical practices, as well as in the general field of research, one so engaged employs devices such as microscopes and other optical aids to enable the monitoring of the procedures and to provide both permanent and visual records of the progress. In particular, the field of neurosurgery requires the physician or surgeon to employ a microscope to enable him to adequately and reliably perform the delicate operation. Hence, there exists many microscopes which are employed both in surgery and in research to enable one to accurately view the condition of the area affected and to provide a permanent record of this area as the operation or research progresses. Hence, such instruments have been referred to as operating room or surgical microscopes.
In modern day practice, a television camera is coupled to the optical path of the microscope to enable the surgical team to follow the procedures on a television monitor. A 35 millimeter or equivalent camera is also required and coupled to the optical path of the microscope to take permanent pictures for purposes of medical records, lectures, papers and so on. While the surgeon must have access to the main eyepiece of the microscope, a further coupling to the optical path of the microscope is afforded to enable a surgical assistant to observe the procedure as it progresses. Hence as can be seen, there are at least three essential attachments required during surgery and which are desirably coupled to the optical path of the microscope.
Generally speaking, the prior art permits the coupling of a maximum of two devices to the optical path of a microscope. If a third device is to be employed, then one attachment must be removed and replaced. This, of course, implies the loss of a valuable viewing aid as well as the time and concentration expended in connecting and disconnecting apparatus.
In general, the prior art uses an optical beam splitter which is positioned in the optical path of a microscope. The beam splitter has two ports for attaching external equipment thereto, and hence one port may accommodate a television camera while the other port may accommodate a surgical assistant's stero microscope or a camera, and so on.
The difficulty with a beam splitter is the limited number of ports. The limitation on the number of ports is due to the loss of light experienced when a beam splitter is employed. Basically, the beam splitter may include a suitable prism or associated lenses which split the microscope light beam and direct the optical energy to both ports. While such beam splitters can increase the amount of light at a port, they do so by reducing the amount of light to the main microscope. A further problem exists in that the coupling of an instrument to a port of the beam splitter requires an appropriate lens or optical matching assembly to enable proper use.
In the operating room microscope, the beam splitter as indicated, is employed to divide the main beam of light. The main beam of light in a microscope comprises parallel rays and hence, the light emanating from the ports of the beam splitter are also parallel. To use a port with a camera as a television or 35 millimeter device requires that the light be focused or directed to form a suitable image size for the camera. Thus the instruments to be employed at the ports of a beam splitter have to be both mechanically and optically coupled to enable proper operation.
Thus the present invention is concerned with an optical coupling device or adapter which has an input port for attachment to a first port of a beam splitter. The device has two outputs to enable the coupling of a television or movie camera to one output and a 35 millimeter or other camera to the other output. The cameras thus coupled to the adapter can be selected during an operation by a switch, which determines which device will be exposed to the optical beam. The coupler or adapter devices further assure that the camera associated with an output receives an optically correct image. Thus, one is enabled to monitor the operation by both, for example, a television and a permanent camera, while leaving one port of the beam splitter free to accommodate a surgical binocular tube for use by a surgical assistant. A switch permits control of the adapter so that the user can switch from the television camera mode to a permanent camera mode simply and reliably while further assuring that the light rays directed to the photographic equipment are properly sized and focused.